ANTIMICROBIAL ACTIVITY OF EXTRACTS OBTAINED FROM THE DUAL INTERACTION BETWEEN SAPROPHYTIC MICROM

Abstract

Background: Saprophytic micromycetes are recognized for their extraordinary ability to biosynthesize various metabolites with biological properties that can be modified when interacting with other organisms. Objective: To evaluate the antibacerial and antifungal activity of extracts obtained from dual interactions of Acremonium masseei CICY029 (Am), Beltraniella portoricensis MR42 (Bp), Cylindrium elongatum MR45 (Ce) y Stachybotrys sp. MR33 (Ssp) and to obtain the chemical profile of the most active interaction. Methodology: The ethyl acetate extracts of the four strains and their six dual interactions were evaluated against ten pathogens by the microdilution method to determine their antifungal and antibacterial capacity.  The most active extracts were partitioned, and the minimum inhibitory concentration (MIC) o their fractions were determined. The chemical profile of the most active interaction was analyzed by gas chromatography coupled to mass spectrometry. Results: The highest mycelial growth inhibitory activity (MCI = 100%) was obtained from the fungal extracts of the single culture of Stachybotrys sp., and the dual Ce-Ssp interaction against Colletotrichum gloeosporioides, Mycosphaerella fijiensis at the concentration of 2000 µg/mL, as well as against Candida albicans and Xanthomonas campestris at 400 µg/mL. The acetonitrile fraction of Stachybotrys sp. showed high effectiveness against Alternaria tagetica, C. gloeosporioides, M. fijiensis and X. campestris (MIC ≤ 250 -1000 µg/mL). A mixture of fatty acids and three unidentified components not observed in the single cultures were detected by GC-MS in the Ce-Ssp extract. Implications: Biological interactions between two saprophytic fungi are a viable alternative for inducing the production of new metabolites with the potential to control pathogenic bacteria and fungi. Conclusions: The antifungal and antibacterial potential of saprophytic micromycetes can be improved in their dual interaction, particularly between C. elongatum MR45 and Stachybotrys sp. MR33, is a promising option for further investigation as potential natural antimicrobials.